% function to caluculate 
% fischer distribution
% to be used with bivariate error calculation
% essentially a remake of it's modula2 version
% latest date 30.07.2002

function[w] = fischer(nue),

      if nue < 6.0,

        w = 5^(nue+1.0);

      else,

     %  ya = 0.4670;   % 32% error 

   %     ya = 1.1746;   %(* 12% error *)
  			ya = 1.6446;   %5 error *)

        h  = 2.0 /(1.0/(nue-5.0) + 1.0/3.0);
        al = (ya * ya) / 6.0 - 0.5;
        w  = ya * sqrt(h+al)/h - ((1.0/3.0) - 1.0/(nue-5.0)) * (al + (5.0/6.0) - (2.0/3.0)/h);

        w = exp(2*w);

	end;



